Seth is an indexing and information architecture consultant, specializing in the construction of navigable information hierarchies, knowledge retrieval systems, and indexes. He is an industry leader in editorial indexing and search and database keywording.

Seth is an adjunct instructor at Bentley College, Middlesex Community College, and Simmons College, all in Massachusetts. His acclaimed interactive online-learning indexing course is only one of two in the global industry. Seth served on the national board of the American Society for Indexing (ASI), including as president in 2006-7.

Seth has worked independently with a large variety of clients, such as the United Nations Library, Mattel, the Massachusetts Institute of Technology, Caterpillar, Mercedes-Benz, Elsevier, and PeopleSoft. Notable former in-house positions include senior integration manager at Terra Lycos, and senior indexer at O'Reilly & Associates. He has written several articles for professional print and online periodicals and presents regularly on topics related to indexing, information architecture, search and keywording, and taxonomy.